well, me, I wrote to the exhaust firm in very bad German, got no reply. Text below.
If any kind German member would like to write or phone him and ask them to state whether their exhaust header fits the LHD Spider with rack and pinion steering I'd be pleased to hear.

Thanks Guy - I didn't have a clue what you wrote but it all sounded good to me. I could definitely find a home for one of these manifolds if they stock them. I think from looking at the site that they probably do.

I'm in the middle of a rack and pinion steering conversion on my 1969 124 Spider AS. I've found all parts of the latest (post 1985-5) Spider DS except the steering arms as bolted to the king pin / steering knuckle. They do differ from the ones used with the regular steering box. Using the old ones will probably induce bump steer and or a change in turning radius.

Can one of the respected members help me out with pictures comparing the pre 1985-5 with post 1985-5 (rack and pinion) steering arms. Any measurements would also be appreciated. This'll help in assessing wether I can modify a regular set. Any leads to a pair for sale will also be highly appreciated.

I have a crossmember off an 85.5 spider, a 131 rack, and those steering arms. I have both sets off the car so I can help you out. I wan to keep them as I want to make this conversion at some point. I would be interested is knowing what you have done on your conversion too if we could swap notes.

Missed your reply this weekend during my daily check inns; sorry for that. If you could make and post side to side photos from different angles comparing the steering arms that would be great.

* So far I have removed all the front suspension with the engine in situ on my car lift.
* During removal of the cross member two bolts (one on the right and one on the left) were spinning so I had to remove them using a disc grinder. I have replaced the bolts from the under side of the rail.
* The DS crossmember differs from the AS one (and possibly all European pre 1976 models) in that the crossmember itself is "lowered" 5 mm below the frame rails and engine mounts. This has been done by adding a 5 mm thick steel bars onto the crossmember and between the crossmember engine mount supports. See attached photos. I have removed these steel bars to make the crossmember height in respect to the car as intended for my 1969 AS.
* Next ops will be to install the modified cross member and related suspension/steering parts. (No steering arms at this moment of course).